Control - or - a little more about Northwoods Deep
Regimes/governments throughout history have exerted control over the populace through coercion and fear. This is reflected in literature/movies quite often; 1984, A Handmaid's Tale, The Killing Fields, pretty much anything to do with the Nazis - you get the picture.
So at one point a while back, I wondered about controlling a populace by giving them what they want - or at least what they think they want. This culminated in my short story 'Mr. Blue' (available in Bedtime Stories for the Apocalypse, plug, plug, plug) in which a population has access to all the 'happy' drugs and sex they wanted. This keeps them docile for the most part, keeps them from noticing or caring that they were basically prisoners in their apartment complexes.
I also used this idea for the evil entity in my novel Northwoods Deep. It keeps its 'guardian' loyal by exploiting its innermost wants and desires, giving it mind-blowing, and very addictive hallucinations; dreams, really, but extremely vivid and realistic, so they feel as if they're actually living them. This keeps the guardian (in this case, an old man named Augustus Meyer) willing to do whatever it takes to keep this entity alive and well fed - even if its food includes a variety of people.
I suppose this isn't much different than the ancient Romans, for example, giving their population the Colosseum - controlling the population's blood-lust by letting them live vicariously through the savage tournaments that took place there. (Which of course has its modern day equivalents, too.)